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Section 8: Harmony and Tuning
Diatonic and Chromatic Harmony
We've described scale and chord harmonies as diatonic,
and shift harmonies as chromatic; but what do those words
mean?
Look at a piano keyboard. Between middle "C" and the
next "C" there are twelve keys - 7 white keys and 5 black
keys. Each of those keys are pitched one semitone apart
for a total of, you guessed it, 12 semitones. The chromatic
scale uses all twelve semitone notes opposed to the
diatonic scales. Thus there is only one chromatic scale, but
12 each of the major, minor, etc. diatonic scales (C major,
C# major, D major, etc). Most of us have grown up hearing
the traditional "doh ray me fah so la tee doh" diatonic
scale, so that harmonies based on the diatonic scale sound
correct.
What does this mean, harmony-wise?
Diatonic scale harmonies can only use notes from the
underlying diatonic scale, so a “third above” harmony voice
actually varies between 3 and four semitones above the
lead note where the chromatic harmony would stay exactly
4 semitones (a major 3rd) above each note.
To recap: we have three different harmony modes that use
chromatic or diatonic scales.
Shifting, which uses the chromatic, 12 semitone scale,
changes the input pitch by a fixed number of semitones:
Chord, which uses the root, third, fifth and sometimes
seventh of the many diatonic scales, pitches the harmony
voice to the closest note contained within the chord:
Scale, which uses one of many diatonic scales, pitches the
harmony voice to the nearest note contained within the
scale:
Theory aside, the best way to get great sound is to
experiment with all of VoicePro's possible harmony modes.
Not only will you develop an intuitive sonic sense of what
works best where, but by investigating different
permutations and combinations you could discover some
delightful sounds you might otherwise have missed.
Just Tuning
What is Just tuning (or Just intonation)? This is the practice
of maintaining the relative and perfect mathematical ratios
between pitches, creating “perfect” harmonies. Just tuning
is different from Equal temperament tuning which is what
most of us use and hear everyday. Equal temperament
uses approximations for the tuning of each note, allowing
us to easily alter the key of our music without re-tuning our
instruments. Although probably no one has ever told you
this, your expensive grand piano and the last great
keyboard synthesizer you bought are both out of tune!
Well, to be fair we can say instead that they are all tuned
using Equal temperament.
Harmony is the result of the interaction between differing
audible frequencies in ratios that sound musical to the
human ear. A more exact ratio leads to a nicer sounding
harmony. Most instruments like the piano are absolute by
nature, meaning that each note has a specific pitch.
Unfortunately, with this method of tuning we lose the ability
to create perfect ratios when playing multiple notes. As a
result, much of the harmony you’ve heard in music has not
been perfectly in tune!
Singers, especially when performing multi-part a cappella
(no accompaniment) music, base their tuning on how it
harmonically sounds with other singers. The natural
tendency, and what sounds best, is to sing with Just tuning
so that inharmonic “beating” is minimized. One of the goals
in Barbershop quartet singing is to strive for “Just relative
intonation” so that a sub-frequency is audible. Achieving
this goal results in what Barbershop fans often describe as
the coveted "ring and lock" sound. In Barbershop music it
is the lead singer's responsibility to try to sing the melody
as close to the tuning of a piano (equal temperament) as
possible. The other singers must then tune their harmonies
to the melody using Just relative intonation. VoicePro is
able to do this in both the Just and Barbershop tuning
modes.
When the Just or Barbershop Modes are selected in the
VoicePro, the harmony tunings are based on the following
relationships:
Minor 3rd = 3 cycles for every 4 cycles of the input
Major 3rd = 5 cycles for every 4 cycles of the input
5th = 3 cycles for every 2 cycles of the input.
Barbershop differs from Just tuning in Chord mode. Just
tuning will use the root of the chord for the tuning
reference, while Barbershop tuning uses the input notes as
the tuning reference. For this reason it is better to use
Barbershop in an a-cappella situation and Just when
playing with other instruments, because Just tuning sounds
more in-tune with the other instruments that most likely
have Equal temperament tuning.
Our best advice is to experiment and use your ears!
